Fine timing synchronization using power delay profile for OFDM systems

Timing synchronization is more critical in orthogonal frequency division multiplexing (OFDM) systems than in single carrier systems. In this paper, a timing estimation scheme is derived from maximum likelihood estimation (MLE) using power delay profile. It is implemented using a delay locked loop (DLL) to achieve fine timing synchronization for OFDM systems. With this scheme, the mean-square error of symbol timing estimation is decreased by orders of magnitude when compared to the simple peak-finding scheme in multipath fading channels. This scheme also shows higher tracking accuracy for symbol timing drift caused by the sampling clock frequency offset.

[1]  Ge Jian-hua.  OFDM Timing Synchronization under Multi-Path Channels , 2005 .

[2]  M. Faulkner,et al.  Timing Synchronization for 802 . 11 a WLANs under Multipath Channels , 2003 .

[3]  John M. Cioffi,et al.  The effect of timing jitter on the performance of a discrete multitone system , 1996, IEEE Trans. Commun..

[4]  Tung-Sang Ng,et al.  Timing-synchronization analysis for IEEE 802.11a wireless LANs in frequency-nonselective Rician fading environments , 2004, IEEE Transactions on Wireless Communications.

[5]  Marc Moeneclaey,et al.  BER sensitivity of OFDM systems to carrier frequency offset and Wiener phase noise , 1995, IEEE Trans. Commun..

[6]  Zhigang Cao,et al.  Timing recovery for OFDM transmission , 2000, IEEE Journal on Selected Areas in Communications.

[7]  Lajos Hanzo,et al.  OFDM and MC-CDMA for Broadband Multi-User Communications, WLANs and Broadcasting , 2003 .

[8]  Hae-Sock Oh,et al.  Frame selection algorithm with adaptive FFT input for OFDM systems , 2002, 2002 IEEE International Conference on Communications. Conference Proceedings. ICC 2002 (Cat. No.02CH37333).

[9]  Robert Barnard Heaton,et al.  OFDM timing synchronisation under multi-path channels , 2003, The 57th IEEE Semiannual Vehicular Technology Conference, 2003. VTC 2003-Spring..

[10]  Heinrich Meyr,et al.  Synchronization in digital communications , 1990 .

[11]  Heinrich Meyr,et al.  Frame synchronization of OFDM systems in frequency selective fading channels , 1997, 1997 IEEE 47th Vehicular Technology Conference. Technology in Motion.